Influence of agricultural management on bat activity and species richness in vineyards of central Chile

Abstract

Agricultural intensification is one of the major causes for the global loss of biodiversity and associated ecosystem services. As an alternative to conventional farming, organic management is considered a way to mitigate some of the negative impacts on biodiversity in agricultural landscapes; however, their benefits for bats are not very conclusive. We investigated the hypothesis that organic farming benefits bats in vineyards by improving conditions for foraging through increased availability of prey. We also hypothesized that bat activity would vary between edges and the interior of vineyards in response to prey availability that in turn would be influenced by agricultural management. Bat activity was quantified along edge and the interior of each vineyard type by using acoustic surveys. In addition, we sampled nocturnal flying insects at each site using light traps. Species richness and overall bat activity were significantly higher in organic than conventional vineyards, with organic edges concentrating the highest bat activity. Our results suggest negative effects of agricultural intensification on insectivorous bats. The high bat activity along edges compared to the interior of vineyards suggest that these structural features of the landscape are important components for bat populations in vineyards, and therefore should be considered within agricultural management in order to promote bat abundance and their role as pest suppressors.